1. Field of the Invention
This invention relates to an electrographic process of producing, on a dielectric coated record medium, an electrostatic copy latent image by modulating a flow of corona ions with the aid of an electrostatic latent image which has been produced on a photoconductive photosensitive screen having a number of openings.
2. Description of the Prior Art
Various kinds of the above described electrographic processes have been well known. In such conventional electrographic process, the electrostatic copy latent image produced on the dielectric coated record medium is developed to obtain a copy picture image or the developed image is transferred to another record medium to obtain a copy picture image. The copy picture image thus obtained is decomposed into picture elements due to the openings of the photoconductive photosensitive screen. As a result, the conventional electrographic process has the drawbacks that the resolving power of the copy picture image becomes degraded, that the concentration of a thin line-shaped picture image becomes smaller than that of a thick line-shaped picture image, and that the contour of the peripheral portions of the picture image becomes unclear.
The above described drawbacks are caused by a phenomenon that the electric field established between the photoconductive photosensitive screen and the dielectric coated record medium is disturbed by the electrostatic copy latent image produced on the dielectric coated record sheet.
Experimental tests have demonstrated the result that the above mentioned phenomenon is associated with an intensity of the electric field established between the photoconductive photosensitive screen and the dielectric coated record medium, a maximum surface potential of the electrostatic copy latent image produced on the dielectric coated record medium, an electrostatic capacity of the dielectric coated record medium, etc.